This is how you can get the median value of a column in PostgreSql. Thanks to http://old.nabble.com/SELECT-TOP–d-PERCENT,-or-SELECT-…-LIMIT–d-PERCENT—td19941366.html
WITH c AS (select count(*)/2 as n from FOO) select COL from FOO order by COL asc limit (1) offset (select n from c);
It is much simpler if you are using SQL Server as described in: http://www.sqlmag.com/Article/ArticleID/49827/sql_server_49827.html
SELECT MAX(Value) FROM (SELECT TOP 50 PERCENT Value FROM dbo.VOrders ORDER BY Value) AS H1; -- Reza++